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A Rough Road from Swords to Ploughshares

By Matthew L. Wald November 19, 2012 7:44 amNovember 19, 2012 7:44 am

National Nuclear Security AdministrationA rendering of a plant in South Carolina that will turn plutonium from bombs into fuel for civilian reactors. Critics worry that the Nuclear Regulatory Commission will relax the rules for the plutonium’s transport.

For nearly 20 years, the Energy Department has been seeking to destroy plutonium recovered from surplus nuclear bombs by converting it to fuel for civilian reactors. Most of it would be destroyed by fission, and the remainder would be embedded in highly radioactive fission products.

Anti-proliferation groups are eager to see the plutonium destroyed as part of a Russian-American agreement because as long as it exists, it can be refashioned into nuclear bombs. But some of those groups oppose accomplishing that through use as fuel in civilian reactors because that would involve a form of commerce in which it could go astray, they say.

Now the Energy Department is building a factory to turn the plutonium from bombs, which is in metal form, into fuel for reactors in a ceramic form. Simultaneously, the staff of the Nuclear Regulatory Commission is looking for ways to relax the security rules on plutonium, which were drafted for the material in bomb form, not fuel form. But opponents are gearing up to fight its use as fuel, focusing on the way it will be transported.

Plutonium is a “special nuclear material,” a government term for bomb fuel, and under Nuclear Regulatory Commission rules, if the quantity is large enough and it is defined as “category 1,” it can be moved only in special trucks and with a variety of security precautions similar to those used for transporting a nuclear weapon. According to a document obtained from the commission by the Union of Concerned Scientists under the Freedom of Information Act, that is what the commission’s staff is considering trying to change.
“The domestic commercial transport capability for Category I S.N.M. is not available,” notes the document, dated September 2009.

The commission’s staff writes that because the fuel plutonium is a ceramic, it is considerably less attractive to a would-be bomb maker than plutonium metal would be. (Assembling a critical mass, the minimum amount needed for a bomb, means squeezing a lot of plutonium into a small space. Its density is higher as a nearly-pure metal than when it is combined with oxygen and low-grade uranium in a ceramic.)

So the staff proposed taking a “material attractiveness approach.’’

Fabricated into fuel assemblies for power reactors, the plutonium would be part of an assembly that weighs 500 to 600 kilograms (1,100 to 1,320 pounds), too much to pick up and run with, the staff said.

At present, if a shipment contains five kilograms (11 pounds) or more of highly enriched uranium, another bomb fuel, the rules do not differentiate between whether it is in a pure form or dispersed in a rail car filled with contaminated soil. So the staff has been issuing exemptions to certain rules. That makes the regulatory system less transparent and also more difficult to administer.

But Edwin Lyman, a physicist and nuclear expert at the Union of Concerned Scientists, said that in contrast to making plutonium, which usually requires a reactor and then complicated chemical processing plants that can handle such highly radioactive material, purifying the plutonium from the form used in fuel requires only “relatively simple chemistry” — namely mixed oxide, or MOx. An adversary could blow up a fuel assembly and cart off the pieces, he said.

“The managers of the U.S. MOx program, which was initiated as part of a bilateral effort with Russia to reduce the threat of unsecured plutonium in both countries, are once again undermining nuclear security by lobbying for a weakening of security measures because of their cost and inconvenience,’’ Dr. Lyman wrote in a paper presented last year at a meeting of the Institute of Nuclear Materials Management.

It makes little sense to relax rules involving a potential bomb fuel at a time when concern about terrorism remains high, he said.

The commission voted to let the staff proceed with a rewrite of the rules. But it did not sound enthusiastic. One commissioner, William Magwood IV, said, “This subject has not yet matured to the stage where the commission should consider a change in current policy.”

In any case, the Energy Department is having trouble recruiting a civilian reactor to use the fuel. Duke accepted some test assemblies for its Catawba nuclear plant in York County, S.C. It used them for about three yeas. But according to Rita Sipe, a spokeswoman, the company decided not to renew its contract with the Department of Energy, primarily because it could not be assured of a fuel supply.

The Energy Department often misses deadlines, and Duke wanted such assurances. Last year an industry publication, Fuel Cycle Week, explained that questionable reliability is one reason that the Energy Department has been having trouble selling the plutonium-based fuel.

At the commission, David McIntyre, a spokesman, said the regulatory work on that front was a low priority. “The industry has given us no indication that they expect to begin using MOx in commercial reactors in the next year or two, so there is no urgency on this issue,’’ he said.

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